Traction means for vehicle-wheels.



H. A. JOHNSTON.

TRACTION MEANS FOR VEHICLE WHEELS.

APPLICATION FILED FEB. 3,1913

Patented Feb. .2, 1915 2 SHEETS-SHEET 1.

I I I I I 1 I a F! a I n I I I I I I I a u I l Fayf). 4 8

WITNESSES ATTORNEY H. A. JOHNSTON, TRACTION MEANS FOR VEHICLE WHEELS. v v APPLIGATION FILED FEB. 3. 1913 1,197,3 9, Patented Feb. 2, 1915 2 SHEETS-SHEET 2.

WifNEssEs ATTORNEY T ing freely, comes into contact with the I the above feature.

ground while still considerably inclined, its rear edge, that is, the edge which first comes in contact with the ground, tends to dig into the ground. To obviate this difiicult the ends of the track supports are curve upwardly so that, .when moving-in either direction, the rear end of the track support, if it should not swing freely, will, when it comes in contact with the ground force the track support to a horizontal position. I also form the track supports with u wardly curved side ed es. This is done to acilitate the turnin o the vehicle, for it is found that, in ma ing such a turn, if the track support is made with its side edges level with the bottom of the support, then, when the wheel turns, the track support w1ll di into the ground ,at the side toward whic the wheel is turning. This greatly retards the action of the vehicle wheel and renders it impossible to make a short turn with 1t. As this device is designed primarily for drawing cultivators, plows and the like through orchards and vineyards where it is necessary to make short turns, the advantage of this construction is obvious.

It is an im ortant feature of'my invention that the tradk supports are so transversely connected with the track sections that the upper surfaces of the ends of said track supports are at a considerable depth below the lower surfaces of the track sections with which they are so connected, that is, so that said track supports can be inclined longitudinally to said track sections at a considerable an le. I have illustrated the advantage of t is construction in traveling over level but uneven ground in Figs. 5 and 6, Fig. 5 illustrating my construction in which the upper surface of the track support is at considerable depth below the lower surfaces of the corresponding track sections, while Fig. 6 illustrates a device in which this feature is lacking. It will be observed that with myconstruction the track supports can rest on uneven ground at a very considerable angle with each other while the track sections are substantiall level. With the construction show 6-this is not the case. In Fig. three track supports whereas in F1 6, it is only supported on two of them. laikewise on ground such as that illustrated in Fig. 7 the wheel is supported on three track sup ports, which would not be the case without Again when passing over a ridge or elevation, when the aforesaid feature is not present in the device, the effect would be, as illustrated in Fig. 10, that as the wheel passed over the apex of said ridg or elevation, and began to descend on its 0 her side that a teetering or balancing action would take place having the apex of be incline 1n 1%. the w eel is supported bythe ridge as a fulcrum. As shown in the Fig. 9, with this feature of the construction no such teetering efl'ect occurs, but the wheel makes a gradua ascent and descent, this be-v ing due to the construction by which the track supports may be considerably inclined to the track sections.

The reason for providing pivots 16 extending in the longitudinal or circumferential directions of the wheel is that the track supports can swing transversely to the wheel so as to enable the. wheel to travel over uneven ground, the track supports conforming in inclination to that of the surface of the ound. Were this transverse movement 0 the track su ports not permissible, the result would be t at, if any one or more track supports, in passing over uneven ground, were not horizontal, but inclined to one side,.in consequence of .which the wheel would ride on one side of the track as illustrated in Fig. 11, which not only quickly wears out the device but greatly reduces the traction surface. By providing this transverse freedom of movement of the track supports, the track sections will not transversely even when moving over uneven ground, as illustrated in Fig. 10.

I claim 1. The combination, with a vehicle wheel,

of track sections, having at their ends downward extensions, transverse pivot pins through said extensions whereby said track sections are pivotally connected together in a circular series around the wheel, each track section having means for en aging the wheel to prevent separation there om, a series of track supports, a yoke for each track so port, a longitudinal pivot pin by which said support is pivoted to the yoke, the sides of the yoke being pivoted on the adjacent'los transverse pivot pin, the upper surface of the sides and ends of each track support be ing sufiiciently below the lower surfaces of said adjacent sections to permit it to swing longitudinally and transversely.

2. The combination, with a vehicle wheel, of track sections, having at their ends outer downward extensions and central downward extensions each between the outer extensions of an adjacent section, a transverse pivot pin through each central extension and the adjacent outer extensions, whereby said track sections are pivotally connected together in a circular series around the wheel, each track section having means engaging the wheel to prevent separation therefrom, a series of track supports, a yoke for each track support, having a rounded surface in contact therewith, alongitudinal pivot pin by which said support is pivoted to the yoke, the sides of the yoke being pivoted on the adjacent transverse pivot pin, the said central and outer extensions having rounded middle my hand in the presence of two subscribing support wltneses.

HARRY A. JOHNSTON.

Witnesses:

FRANCIS M. WRIGHT, D. B. Rrcmmns, 

